package com.glgc.projecti.common;
import java.util.ResourceBundle;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.digest.DigestUtils;

/*字符串 DESede(3DES) 加密
 * 3DES（即Triple DES）是DES向AES过渡的加密算法（1999年，NIST将3-DES指定为过渡的
 * 加密标准），是DES的一个更安全的变形。它以DES为基本模块，通过组合分组方法设计出分组加
 * 密算法，其具体实现如下：设Ek()和Dk()代表DES算法的加密和解密过程，K代表DES算法使用的
 * 密钥，P代表明文，C代表密表，这样，
 * 3DES加密过程为：C=Ek3(Dk2(Ek1(P)))
 * 3DES解密过程为：P=Dk1((EK2(Dk3(C)))
 * */
public class TripleDESUtils {

	
	private static final String Algorithm = "DESede"; //定义加密算法,可用 DES,DESede,Blowfish
    //keybyte为加密密钥，长度为24字节    
	//src为被加密的数据缓冲区（源）
	private static byte[] encryptMode(byte[] keybyte,byte[] src){
		 try {
			//生成密钥
			SecretKey deskey = new SecretKeySpec(keybyte, Algorithm);
			//加密
			Cipher c1 = Cipher.getInstance(Algorithm);
			c1.init(Cipher.ENCRYPT_MODE, deskey);
			return c1.doFinal(src);//在单一方面的加密或解密
		} catch (java.security.NoSuchAlgorithmException e1) {
			// TODO: handle exception
			 e1.printStackTrace();
		}catch(javax.crypto.NoSuchPaddingException e2){
			e2.printStackTrace();
		}catch(java.lang.Exception e3){
			e3.printStackTrace();
		}
		return null;
	}
	
	//keybyte为加密密钥，长度为24字节    
	//src为加密后的缓冲区
	private static byte[] decryptMode(byte[] keybyte,byte[] src) throws Exception{
		//生成密钥
		SecretKey deskey = new SecretKeySpec(keybyte, Algorithm);
		//解密
		Cipher c1 = Cipher.getInstance(Algorithm);
		c1.init(Cipher.DECRYPT_MODE, deskey);
		return c1.doFinal(src);
	}
	
    //转换成十六进制字符串
	public static String byte2Hex(byte[] b){
		String hs="";
		String stmp="";
		for(int n=0; n<b.length; n++){
			stmp = (java.lang.Integer.toHexString(b[n]& 0XFF));
			if(stmp.length()==1){
				hs = hs + "0" + stmp;				
			}else{
				hs = hs + stmp;
			}
			if(n<b.length-1)hs=hs+":";
		}
		return hs.toUpperCase();		
	}
	
	private static byte[] hex(){
		//加密关键字，从配置文件读取
		String key = ResourceBundle.getBundle("config").getString("3DES_KEY");
		String f = DigestUtils.md5Hex(key);
		byte[] bkeys = new String(f).getBytes();
		byte[] enk = new byte[24];
		for (int i=0;i<24;i++){
			enk[i] = bkeys[i];
		}
		return enk;
	}

	public static String encode(String rawData) {
		try{
			byte[] encoded = encryptMode(hex(),rawData.getBytes());
			String cipherText = Base64.encodeBase64String(encoded);
			return cipherText;
		}catch (Exception e){
			e.printStackTrace();
			return null;
		}
	}
	
	public static String decode(String cipherText) {
		try{
			byte[] reqPassword = Base64.decodeBase64(cipherText);
			byte[] srcBytes = decryptMode(hex(),reqPassword);
			String plainText = new String(srcBytes);
			return plainText;
		}catch (Exception e){
			e.printStackTrace();
			return null;
		}
	}
	
	public static void main(String[] args) throws Exception {
		
		String rawData = "18626095819";
		System.out.println("加密前的字符串:" + rawData);
		String cipherText = encode(rawData); 
		System.out.println("加密后的字符串:" + cipherText);
		
		String plainText = decode(cipherText);
		System.out.println("解密后的字符串:" + plainText);
	}
}
